Virtual destructors should have virtual keyword.

chrome/browser/bookmarks/bookmark_html_writer.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_BOOKMARKS_BOOKMARK_HTML_WRITER_H_
 #define CHROME_BROWSER_BOOKMARKS_BOOKMARK_HTML_WRITER_H_
 #pragma once
 
 #include <list>
 #include <map>
@@ skipping 23 matching lines @@
 // then starts Writer which outputs bookmarks and favicons to html file.
 // Should be used only by WriteBookmarks function.
 class BookmarkFaviconFetcher: public NotificationObserver {
  public:
   // Map of URL and corresponding favicons.
   typedef std::map<std::string, scoped_refptr<RefCountedMemory> > URLFaviconMap;
 
   BookmarkFaviconFetcher(Profile* profile,
                          const FilePath& path,
                          BookmarksExportObserver* observer);
-  ~BookmarkFaviconFetcher();
+  virtual ~BookmarkFaviconFetcher();
 
   // Executes bookmark export process.
   void ExportBookmarks();
 
   // NotificationObserver implementation.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
                        const NotificationDetails& details);
 
  private:
@@ skipping 43 matching lines @@
 // thread is used.
 // Before writing to the file favicons are fetched on the main thread.
 // TODO(sky): need a callback on failure.
 void WriteBookmarks(Profile* profile,
                     const FilePath& path,
                     BookmarksExportObserver* observer);
 
 }  // namespace bookmark_html_writer
 
 #endif  // CHROME_BROWSER_BOOKMARKS_BOOKMARK_HTML_WRITER_H_